Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number STDGEARSIZE3A found under Coupling Shaft Flex by Somerset Engineering Div. The National Stock Number assigned to this part is 3010012095170, and the Federal Supply Class is 3010 Torque Converters And Speed Changers. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like STDGEARSIZE3A.